1. Field of the Invention
The present invention relates to natural language understanding systems, and more particularly to a method and system for non-intrusively verifying a user based on behavior of the user.
2. Description of the Related Art
Traditional methods for speaker verification (or identification) rely on specific inputs from the user for the sole purpose of the verification. These methods may include providing speech samples and answering biometric questions. Once verified, the speaker is permitted to access the target system, and typically no further verification is performed. Even if additional verification is performed, it requires more specific inputs from the user for the purpose of verification. This is intrusive to the user.
Prior art speaker verification systems (or user verification systems, for systems without a spoken input modality) validate the identity of a given user on the basis of one or more of the following criteria:                1. Who the user is, which may be determined by the user's voice, fingerprint, handwriting, etc.        2. What the user knows, which may be determined by a password, or answers to some biometric questions (e.g., what is the mother's maiden name?), etc.        3. What the user possesses, such as an identification document, a key, a cellular phone with a particular number, etc.        
All of the above methods for verification may be defeated if an imposter knows or possesses the information, such as the key or a maiden name, etc.
Therefore, a need exists for a method and system for determining an identity of a user based on the users behavior. A further need exists for a non-intrusive user verification system.